D. J. Bernstein
UNIX
daemontools

How to start daemontools

There are several different ways to run the svscanboot command, starting svscan. None of these ways are portable; UNIX/Linux distributors keep screwing around with their startup systems, breaking compatibility with existing startup scripts.

/etc/rc.local

Put the line 
     csh -cf '/command/svscanboot &'
at the end of /etc/rc.local.

Portability: This is the traditional approach.

/etc/inittab

Put the line 
     SV:12345:respawn:/command/svscanboot
at the end of /etc/inittab.

Portability: This is the traditional System V approach, and was almost universally supported among Linux systems for years, but was broken by Ubuntu 6.10.

/etc/event.d version 1

Put the lines 
     start on runlevel-1
     start on runlevel-2
     start on runlevel-3
     start on runlevel-4
     start on runlevel-5
     respawn /command/svscanboot
into /etc/event.d/svscan.

Portability: This worked under Ubuntu 6.10 but was broken by Ubuntu 7.04.

/etc/event.d version 2

Put the lines 
     start on runlevel 1
     start on runlevel 2
     start on runlevel 3
     start on runlevel 4
     start on runlevel 5
     respawn
     exec /command/svscanboot
into /etc/event.d/svscan.

Portability: This worked under Ubuntu 7.04 through 9.04 but was broken by Ubuntu 9.10.

/etc/init

Put the lines 
     start on runlevel [12345]
     stop on runlevel [^12345]
     respawn
     exec /command/svscanboot
into /etc/init/svscan.conf.

Portability: This works under Ubuntu 9.10 through (at least) 11.10.